What is design
What is design, ever since man has been making things people design prior to making? this could be in the form of just thinking it over in their head and then making their design as they go.
Some people think of it, and put pen to paper draw and access their design. then when they think they have it finalised they make it.
But with the advancements in a computer, the above has been wiped out now a design gets thought of and using a CAD programme people create their design in one of these. There are many CAD programmes to be used.
2D CAD Programmes
3D CAD Programmes
What's the difference
The only difference between 2D and 3D CAD Design programmes is the third dimension.
Do I need to start a 2d programme?
NO, you can go straight into a 3D design you will pick up 2d in a matter of days.
What's The Best Programme
Personally, I always use Solidworks for 3D design, it is a very powerful CAD design package, one issue I found tho is if I want to download a design in .stl format and import it to SolidWorks it tends to play up.
For this issue, I tend to use Google Sketchup as it allows me to import .stl without any issues.
I don't do much 2D design anymore I am qualified in AutoDesk AutoCAD but I very rarely use this programme, if I was to use a 2D programme I would use LibreCAD its free and powerful application.
For someone that is new to design I would say use Google Sketchup you will complete a design within a day and its free, but for someone wanting to advance in 3d design, I would advise using Solidworks.